參照計數

本節中的巨集用於管理 Python 物件的參照計數。

void Py_INCREF(PyObject *o)

Indicate taking a new strong reference to object o, indicating it is in use and should not be destroyed.

此函式通常用於將借用參照原地 (in-place) 轉換為強參照。Py_NewRef() 函式可用於建立新的強參照。

When done using the object, release it by calling Py_DECREF().

該物件不能為 NULL；如果你不確定它不是 NULL，請使用 Py_XINCREF()。

Do not expect this function to actually modify o in any way.

void Py_XINCREF(PyObject *o)

Similar to Py_INCREF(), but the object o can be NULL, in which case this has no effect.

另請見 Py_XNewRef()。

PyObject *Py_NewRef(PyObject *o)

Part of the Stable ABI since version 3.10.

Create a new strong reference to an object: call Py_INCREF() on o and return the object o.

When the strong reference is no longer needed, Py_DECREF() should be called on it to release the reference.

物件 o 不能為 NULL；如果 o 可以為 NULL，則使用 Py_XNewRef()。

舉例來說：

Py_INCREF(obj);
self->attr = obj;

可以寫成：

self->attr = Py_NewRef(obj);

另請參閱 Py_INCREF()。

在 3.10 版新加入.

PyObject *Py_XNewRef(PyObject *o)

Part of the Stable ABI since version 3.10.

與 Py_NewRef() 類似，但物件 o 可以為 NULL。

如果物件 o 為 NULL，則該函式僅回傳 NULL。

在 3.10 版新加入.

void Py_DECREF(PyObject *o)

Release a strong reference to object o, indicating the reference is no longer used.

Once the last strong reference is released (i.e. the object's reference count reaches 0), the object's type's deallocation function (which must not be NULL) is invoked.

此函式通常用於在退出作用域之前刪除強參照。

該物件不能為 NULL；如果你不確定它不是 NULL，請改用 Py_XDECREF()。

Do not expect this function to actually modify o in any way.

警告

The deallocation function can cause arbitrary Python code to be invoked (e.g. when a class instance with a __del__() method is deallocated). While exceptions in such code are not propagated, the executed code has free access to all Python global variables. This means that any object that is reachable from a global variable should be in a consistent state before Py_DECREF() is invoked. For example, code to delete an object from a list should copy a reference to the deleted object in a temporary variable, update the list data structure, and then call Py_DECREF() for the temporary variable.

void Py_XDECREF(PyObject *o)

Similar to Py_DECREF(), but the object o can be NULL, in which case this has no effect. The same warning from Py_DECREF() applies here as well.

void Py_CLEAR(PyObject *o)

Release a strong reference for object o. The object may be NULL, in which case the macro has no effect; otherwise the effect is the same as for Py_DECREF(), except that the argument is also set to NULL. The warning for Py_DECREF() does not apply with respect to the object passed because the macro carefully uses a temporary variable and sets the argument to NULL before releasing the reference.

It is a good idea to use this macro whenever releasing a reference to an object that might be traversed during garbage collection.

void Py_IncRef(PyObject *o)

Part of the Stable ABI.

Indicate taking a new strong reference to object o. A function version of Py_XINCREF(). It can be used for runtime dynamic embedding of Python.

void Py_DecRef(PyObject *o)

Part of the Stable ABI.

Release a strong reference to object o. A function version of Py_XDECREF(). It can be used for runtime dynamic embedding of Python.

以下函式或巨集僅在直譯器核心內使用：_Py_Dealloc()、_Py_ForgetReference()、_Py_NewReference() 以及全域變數 _Py_RefTotal。